-- Restrict delete
ALTER TABLE dbo.tReferTable
ADD CONSTRAINT rfk_tReferTable_tPrimaryTable_FKID FOREIGN KEY
	( FKID ) 
REFERENCES dbo.tPrimaryTable
	( PKID )

-- Delete cascade
ALTER TABLE dbo.tReferTable
ADD CONSTRAINT rfk_tReferTable_tPrimaryTable_FKID FOREIGN KEY
    ( FKID ) 
REFERENCES dbo.PrimaryTable
    ( PKID )
ON DELETE CASCADE